得到具体路径快的所有文件和目录 [英] Get all files and directories in specific path fast

问题描述

我创建其中c＃扫描目录的备份应用程序。之前，我用它来有这样的事情，以获得目录中的所有文件和子文件：

I am creating a backup application where c# scans a directory. Before I use to have something like this in order to get all the files and subfiles in a directory:

DirectoryInfo di = new DirectoryInfo("A:\\");
var directories= di.GetFiles("*", SearchOption.AllDirectories);

foreach (FileInfo d in directories)
{
       //Add files to a list so that later they can be compared to see if each file
       // needs to be copid or not
}

与唯一的问题是，有时文件无法访问，我得到几个错误。我得到一个错误的一个例子是：

The only problem with that is that sometimes a file could not be accessed and I get several errors. an example of an error that I get is:

因此​​，我创建了将扫描当前目录中的所有文件的递归方法。如果在那里有在该目录的目录，则该方法将被再次调用传递该目录。这个方法的好处是，我可以放置一个try catch块里面让我将这些文件添加到列表中选择文件，如果那里有没有错误，并添加目录到另一个目录，如果我有错误。

As a result I created a recursive method that will scan all files in the current directory. If there where directories in that directory then the method will be called again passing that directory. The nice thing about this method is that I could place the files inside a try catch block giving me the option to add those files to a List if there where no errors and adding the directory to another list if I had errors.

try
{
    files = di.GetFiles(searchPattern, SearchOption.TopDirectoryOnly);               
}
catch
{
     //info of this folder was not able to get
     lstFilesErrors.Add(sDir(di));
     return;
}

所以这种方法的伟大工程，唯一的问题是，当我扫描大型目录花费太多时间。我怎么能加快这一进程呢？我实际的方法是这样的情况下你需要它。

So this method works great the only problem is that when I scan a large directory it takes to much times. How could I speed up this process? My actual method is this in case you need it.

private void startScan(DirectoryInfo di)
{
    //lstFilesErrors is a list of MyFile objects
    // I created that class because I wanted to store more specific information
    // about a file such as its comparePath name and other properties that I need 
    // in order to compare it with another list

    // lstFiles is a list of MyFile objects that store all the files
    // that are contained in path that I want to scan

    FileInfo[] files = null;
    DirectoryInfo[] directories = null;
    string searchPattern = "*.*";

    try
    {
        files = di.GetFiles(searchPattern, SearchOption.TopDirectoryOnly);               
    }
    catch
    {
        //info of this folder was not able to get
        lstFilesErrors.Add(sDir(di));
        return;
    }

    // if there are files in the directory then add those files to the list
    if (files != null)
    {
        foreach (FileInfo f in files)
        {
            lstFiles.Add(sFile(f));
        }
    }


    try
    {
        directories = di.GetDirectories(searchPattern, SearchOption.TopDirectoryOnly);
    }
    catch
    {
        lstFilesErrors.Add(sDir(di));
        return;
    }

    // if that directory has more directories then add them to the list then 
    // execute this function
    if (directories != null)
        foreach (DirectoryInfo d in directories)
        {
            FileInfo[] subFiles = null;
            DirectoryInfo[] subDir = null;

            bool isThereAnError = false;

            try
            {
                subFiles = d.GetFiles();
                subDir = d.GetDirectories();

            }
            catch
            {
                isThereAnError = true;                                                
            }

            if (isThereAnError)
                lstFilesErrors.Add(sDir(d));
            else
            {
                lstFiles.Add(sDir(d));
                startScan(d);
            }


        }

}

蚂蚁的问题，如果我尝试处理与类似的异常：

Ant the problem if I try to handle the exception with something like:

DirectoryInfo di = new DirectoryInfo("A:\\");
FileInfo[] directories = null;
            try
            {
                directories = di.GetFiles("*", SearchOption.AllDirectories);

            }
            catch (UnauthorizedAccessException e)
            {
                Console.WriteLine("There was an error with UnauthorizedAccessException");
            }
            catch
            {
                Console.WriteLine("There was antother error");
            }

是，如果再发生异常我没有得到任何文件。

Is that if an exception occurs then I get no files.

推荐答案

此方法要快得多。您可以将只有当电话目录中的很多文件。我答：\\外部硬盘驱动器包含了几乎1兆兆位所以它是一个很大的区别有很多文件的时候。

This method is much faster. You can only tel when placing a lot of files in a directory. My A:\ external hard drive contains almost 1 terabit so it makes a big difference when dealing with a lot of files.

static void Main(string[] args)
{
    DirectoryInfo di = new DirectoryInfo("A:\\");
    FullDirList(di, "*");
    Console.WriteLine("Done");
    Console.Read();
}

static List<FileInfo> files = new List<FileInfo>();  // List that will hold the files and subfiles in path
static List<DirectoryInfo> folders = new List<DirectoryInfo>(); // List that hold direcotries that cannot be accessed
static void FullDirList(DirectoryInfo dir, string searchPattern)
{
    // Console.WriteLine("Directory {0}", dir.FullName);
    // list the files
    try
    {
        foreach (FileInfo f in dir.GetFiles(searchPattern))
        {
            //Console.WriteLine("File {0}", f.FullName);
            files.Add(f);                    
        }
    }
    catch
    {
        Console.WriteLine("Directory {0}  \n could not be accessed!!!!", dir.FullName);                
        return;  // We alredy got an error trying to access dir so dont try to access it again
    }

    // process each directory
    // If I have been able to see the files in the directory I should also be able 
    // to look at its directories so I dont think I should place this in a try catch block
    foreach (DirectoryInfo d in dir.GetDirectories())
    {
        folders.Add(d);
        FullDirList(d, searchPattern);                    
    }

}

当我得到这个感谢您的评论吉姆·米契尔的方式

By the way I got this thanks to your comment Jim Mischel

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